The prior art of U.S. Patent Publication 2010/007531 discloses a control device which operates with piezoelectric sensor elements, where bending is detected when a finger is applied to a control panel above the sensor elements.
Furthermore, WO 2007/036247 A discloses how an elongated control device is in the form of a so-called slider, and is operated by application of a finger and drawing it in the form of a line over the slider. In particular, this makes it possible, for example, to set a power in a plurality of levels or in a specific range, very easily and effectively.